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040			_aEC-PaCDF
041			_aeng
082	0	4	_221 _a598.883 KOO
100	1		_aKoop, Jennifer A.
245	1	0	_aExperimental demonstration of a parasite-induced immune response in wild birds: _bDarwin’s finches and introduced nest flies.
520	0		_aEcological immunology aims to explain variation among hosts in the strength and efficacy of immunological defenses. However, a shortcoming has been the failure to link host immune responses to actual parasites under natural conditions. Here, we present one of the first experimental demonstrations of a parasiteinduced immune response in a wild bird population. The recently introduced ectoparasitic nest fly Philornis downsi severely impacts the fitness of Darwin’s finches and other land birds in the Galapagos Islands. An earlier study showed that female medium ground finches (Geospiza fortis) had P. downsi-binding antibodies correlating with presumed variation in fly exposure over time. In the current study, we experimentally manipulated fly abundance to test whether the fly does, in fact, cause changes in antibody levels. We manipulated P. downsi abundance in nests and quantified P. downsi-binding antibody levels of médium ground finch mothers, fathers, and nestlings. We also quantified host behaviors, such as preening, which can integrate with antibody-mediated defenses against ectoparasites. Philornis downsi-binding antibody levels were significantly higher among mothers at parasitized nests, compared to mothers at (fumigated) nonparasitized nests. Mothers with higher antibody levels tended to have fewer parasites in their nests, suggesting that antibodies play a role in defense against parasites. Mothers showed no behavioral changes that would enhance the effectiveness of the immune response. Neither adult males, nor nestlings, had P. downsi-induced immunological or behavioral responses that would enhance defense against flies. None of the parasitized nests fledged any offspring, despite the immune response by mothers. Thus, this study shows that, while the immune response of mothers appeared to be defensive, it was not sufficient to rescue current reproductive fitness. This study further shows the importance of testing the fitness consequences of immune defenses, rather than assuming that such responses increase host fitness.
546			_aEnglish
653			_aAntibody.
653			_aAnticuerpo.
653			_aDefense.
653			_aDefensa.
653			_aEcoimmunology.
653			_aEcoinmunología.
653			_aGeospiza fortis.
653			_aInvasive species.
653			_aEspecies invasoras.
653			_aPhilornis downsi.
700	1		_aOwen, Jeb P.
700	1		_aKnutie, Sarah A.
700	1		_aAguilar, Maria A.
700	1		_aClayton, Dale H.
773	0		_gVol. 3, no. 8 (May 2013), p. 2514-2523 _tEcology and Evolution.
856	0		_uhttp://dx.doi.org/10.1002/ece3.651
942			_2ddc _cARTICLE
999			_c13059 _d13059